In biological fluids, proteins may associate with nanoparticles (NPs), leading to the formation of a so-called “protein corona” largely defining the biological identity of the particle. Here, we ...present a novel approach to assess apparent binding affinities for the adsorption/desorption of proteins to silver NPs based on the impact of the corona formation on the agglomeration kinetics of the colloid. Affinities derived from circular dichroism measurements complement these results, simultaneously elucidating structural changes in the adsorbed protein. Employing human serum albumin as a model, apparent affinities in the nanomolar regime resulted from both approaches. Collectively, our findings now allow discrimination between the formation of protein mono- and multilayers on NP surfaces.
All over the world, different types of nanomaterials with a diversified spectrum of applications are designed and developed, especially in the field of nanomedicine. The great variety of ...nanoparticles (NPs), in vitro test systems and cell lines led to a vast amount of publications with conflicting data. To identify the decisive principles of these variabilities, we conducted an intercomparison study of collaborating laboratories within the German DFG Priority Program SPP1313, using well-defined experimental parameters and well-characterized NPs. The participants analyzed the in vitro biocompatibility of silica and polymer NPs on human hepatoma HepG2 cells. Nanoparticle mediated effects on cell metabolism, internalization, and inflammation were measured. All laboratories showed that both nanoparticle formulations were internalized and had a low cytotoxicity profile. Interestingly, small variations in nanoparticle preparation, cell handling and the type of culture slide influenced the nanoparticle stability and the outcomes of cell assays. The round robin test demonstrated the importance of the use of clearly defined and characterized NPs and parameters for reproducible results across laboratories. Comparative analyses of in vitro screening methods performed in multiple laboratories are absolutely essential to establish robust standard operation procedure as a prerequisite for sound hazard assessment of nanomaterials.
Abstract
Wind turbine rotor blades are heavily loaded composite structures that experience a mixture of aerodynamic, inertial, gravitational, and gyroscopic forces during their operation life. Due to ...the high loads, the cross-sections of the blades are subjected to in-plane and out-of-plane deformations. The out-of-plane deformations are referred to as shear warping while the in-plane deformations are also called blade breathing. Blade breathing depends on the magnitude of the mechanical loads, which are expressed by means of internal forces and moments, and the stiffness of the blade shell.
In this work, the relationships between in-plane cross-sectional deformations and internal loads are investigated. For the quantification of the deformation, a reference blade is studied via 3D finite shell element simulations for different loading scenarios. The cross-section of interest is located at the radial position of maximum chord. To compare the shape of the cross-sections in the undeformed and the deformed configurations, a procedure is proposed to relate the positions of nodes associated with the cross-section of interest in both configurations to a joint coordinate system. The shape of the deformed cross-section is then extracted and compared with the undeformed configuration. The comparison is executed for the individual internal forces and moments, namely flapwise and edgewise bending moments, normal force, shear forces, and torsion moment, respectively. The deformation patterns are discussed and it is addressed how these may influence the aerodynamic behavior of the cross-section under consideration.
Interactions between differently functionalised silver and gold nanoparticles (NPs) as well as polystyrene nanoparticles with bovine serum albumin (BSA) are studied using circular dichroism (CD) ...spectroscopy. It is found that the addition of NPs to the protein solution destroys part of the helical secondary structure of the protein as a result of surface adsorption. From the loss of free protein and hence the extent of their structural change adsorption equilibrium constants are derived. The results reveal that citrate‐coated gold and silver NPs exhibit much stronger interactions with BSA than polymeric or polymer‐coated metallic NPs. It is therefore concluded that for the particles considered, the influence of surface composition on the interaction behaviour dominates that of the core.
Inner space: Interactions between differently functionalised Ag and Au nanoparticles (NPs) as well as polystyrene nanoparticles with bovine serum albumin (BSA) are studied using circular dichroism (CD) spectroscopy (see picture). Citrate‐coated Au and Ag NPs exhibit stronger interactions with BSA than polymeric or polymer‐coated metallic NPs.
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•Synthesis of Zn2SnO4 by reactive laser sintering from ZnO and SnO2 nanocrystals.•High phase purity and nanoscaled microstructure of laser synthesized Zn2SnO4.•Pure and mixed films of ...ZnO and SnO2 via electrophoretic deposition.•Controlled and homogenous film composition due to colloidal processing.
A novel procedure for producing polycrystalline zinc stannate (Zn2SnO4, ZTO) films is presented in this paper. Nanocrystals of zinc oxide (ZnO) and tin dioxide (SnO2) are prepared by chemical vapor synthesis (CVS) and processed into stable aqueous dispersions including mixed colloids. These colloids are transformed into nanostructured films via electrophoretic deposition where the mixed colloid forms a homogeneous, nanoscaled composite. Ultraviolet (UV) laser sintering of these codeposited ZnO-SnO2 nanocrystals generates the inverse cubic spinel Zn2SnO4 phase by chemical reaction on the area of interest. The effects of UV laser sintering at a wavelength of 325 nm on the nanoscaled microstructure of pure deposited films are investigated by variation of laser power and scanning speed. The microstructure of composite films is compared to a film obtained by classical reactive sintering in a furnace. High-resolution scanning electron microscopy and energy dispersive X-ray spectroscopy are used to investigate film morphology and chemical composition. Structural characterization is performed by X-ray diffraction.
Oxide semiconductors are highly suitable materials for solution‐processed/printed electronics (PE); the growing interest in them can be related to their excellent intrinsic properties, such as high ...mobility, optical transparency, thermal and environmental stability, and so on. However, high process temperatures remain as the foremost challenge that may limit the compatibility of printed oxide electronics to inexpensive flexible substrates. Here, the possibility of using photonic curing methods to lower the process temperature is investigated, even down to room temperature (RT). Two distinct ultraviolet (UV) curing techniques, involving UV–visible light pulses and continuous‐wave UV lasers are exercised and compared. Combining UV curing with oxide nanoparticulate channel layer and electrolytic gate insulators, it is demonstrated that high performance field‐effect transistors (FETs) with device mobility as high as 12 cm2 V−1 s−1 can be processed entirely at room temperature and realized on plastic substrates. The fabrication steps include printing of a heavily stabilized semiconducting nanoparticulate channel layer, followed by decomposition and removal of the semi‐insulating polymer ligands using UV‐photon energies. The curing process is found to be fast and high‐throughput manufacturing technique compatible. At the same time, the energy requirement to remove the polymer stabilizers is insignificant, thereby ensuring no temperature rise of the parent substrates.
One of the major challenges for printed oxide electronics is the reduction in process temperature to allow selection of numerous inexpensive substrates. Here, it is demonstrated that printing of polymer‐stabilized nanoparticulate layer as the active channel material and subsequent removal of the polymeric capping agents via UV‐photonic curing enables room temperature processed, high performance field‐effect transistors on plastic substrates.
A preliminary comparison of evacuation times of the Flying V and the Airbus A350-900 is presented in this study. A simple simulation tool based on the technique of cellular automata was created to ...model the evacuation process for different closed door configurations. Certification regulations state that the time to evacuate a civil aircraft in case of an emergency with half of all exit doors closed must be less than 90 seconds. The results of this study indicate that the shorter V shaped cabin has advantages over the longer conventional reference cabin for cases when passengers need to evacuate towards the front or the back of the aircraft. Disadvantages occur when the passengers in the V shaped cabin need to evacuate more towards one side (left or right wing) of the aircraft. A more detailed simulation model to further investigate these cases is currently created by the authors.
All over the world, different types of nanomaterials with a diversified spectrum of applications are designed and developed, especially in the field of nanomedicine. The great variety of ...nanoparticles (NPs), in vitro test systems and cell lines led to a vast amount of publications with conflicting data. To identify the decisive principles of these variabilities, we conducted an intercomparison study of collaborating laboratories within the German DFG Priority Program SPP1313, using well-defined experimental parameters and well-characterized NPs. The participants analyzed the in vitro biocompatibility of silica and polymer NPs on human hepatoma HepG2 cells. Nanoparticle mediated effects on cell metabolism, internalization, and inflammation were measured. All laboratories showed that both nanoparticle formulations were internalized and had a low cytotoxicity profile. Interestingly, small variations in nanoparticle preparation, cell handling and the type of culture slide influenced the nanoparticle stability and the outcomes of cell assays. The round robin test demonstrated the importance of the use of clearly defined and characterized NPs and parameters for reproducible results across laboratories. Comparative analyses of in vitro screening methods performed in multiple laboratories are absolutely essential to establish robust standard operation procedure as a prerequisite for sound hazard assessment of nanomaterials.
Pulmonary Surfactant reduces surface tension in the terminal airways thus facilitating breathing and contributes to host's innate immunity. Surfactant Proteins (SP) A, B, C and D were recently ...identified as inherent proteins of the CNS. Aim of the study was to investigate cerebrospinal fluid (CSF) SP levels in hydrocephalus patients compared to normal subjects.
CSF SP A-D levels were quantified using commercially available ELISA kits in 126 patients (0-84 years, mean 39 years). 60 patients without CNS pathologies served as a control group. Hydrocephalus patients were separated in aqueductal stenosis (AQS, n = 24), acute hydrocephalus without aqueductal stenosis (acute HC w/o AQS, n = 16) and idiopathic normal pressure hydrocephalus (NPH, n = 20). Furthermore, six patients with pseudotumor cerebri were investigated.
SP A-D are present under physiological conditions in human CSF. SP-A is elevated in diseases accompanied by ventricular enlargement (AQS, acute HC w/o AQS) in a significant manner (0.67, 1.21 vs 0.38 ng/ml in control, p<0.001). SP-C is also elevated in hydrocephalic conditions (AQS, acute HC w/o AQS; 0.87, 1.71 vs. 0.48 ng/ml in controls, p<0.001) and in Pseudotumor cerebri (1.26 vs. 0.48 ng/ml in controls, p<0.01). SP-B and SP-D did not show significant alterations.
The present study confirms the presence of SPs in human CSF. There are significant changes of SP-A and SP-C levels in diseases affecting brain water circulation and elevation of intracranial pressure. Cause of the alterations, underlying regulatory mechanisms, as well as diagnostic and therapeutic consequences of cerebral SP's requires further thorough investigations.
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